Battery-charging system.



W. L. BLISS.

BATTERY CHARGING SYSTEM.

APPLICATION FILED MAY 25, IsII. RENEwED APR. 6. I9I7.

41,246,855. Patented Nv. 2o, 1917.

llllllllIl'lllllllP-m-` I :IIIIIIIII UNITED STATES PATENT`o1rr1cn WILLIAM L. BLIss, or NIAGARA rALLs, Nnw Yonx, AssIcNon, BY :msm ASSIGN- MENTS, T0 `U.-S. LIGHT & HEAT CORPORATION, OF NIA-.GARA FALLS, NEW YORK, A

CORPORATION 0F NEW YORK.

Specification of Letters Patent.

Application filed Hay 25, 1911, Serial No. 629,328. Renewed April 6, 1917. Serial No. 160,309. I

clear, concise, and exact description, reter-l ence being had to the accompanying drawing, forming a part of this specification.

My invention relates to means for charging storage batteries.

One of the objects of the invention is to provide an improved regulator for control.

ling the chargingv rate of storage batteries. One use for such a regulator is in stationary service, as in the charging o fthe batteries of an'electric vehicle or in the charging of train lighting batteries lwhich are. chargedat the terminals from the regular constant voltage charging lines in the so-called straight stora e battery service. object of the invention is to provide automatic means for preventing overcharging of the battery. 1

In the accompanying drawings'I have illustrated two embodiments of `the invention. contemplated.

In the drawings Figure 1 illustrates a regulator having a stop charge relay.

Fig. 2 illustrates a regulator having. a taper char relay. Y

In both gures the mains 1, 2, are adapted to supply charging current to thebatteries 3 when the switches 4 are closed. The variable pressure rheostat 5 in each case,.1s connected in series-with the battery. Said rheostat may be assumed to` be typical of any variable resistance. The resistance of the variable pressure rheostat 5 is controlled by a series controlling winding 6, and alsounder certain conditions, by the voltage responsive winding 7. These windings, when ener zed, act directly onA the plunger 8 whic is connected preferably to the bell crank lever 9 which 1n turn acts directly to vary the pressure applied to the variable pressure rheostat. The core 8 andthe bell crank lever 9 are normally in lowermost position, due to their weight, assisted by the spring 10, whereby the resistance of the -variable pressure rheostat is normally a mlm-- Another Other embodiments are, of course,

mum. The dash-pot 11 is adapted to steady the action of the movable parts.

In the form of regulator shown in Fig. 1, the voltage responsive winding 7 is normally inert, beingopencircuited by the piv' oted lever 12, which is controlled by the voltage coil 13, responsive to the voltage at the battery terminals. During the charging of the battery, the series winding 6 controls the variable preure rheostat 5 so as to maintain substantially' constant the current supplied to the battery 3.- -As the battery approaches afully charged condition, however, the counter electro-motive force developed thereby causes an increased energization of the voltage coil`13, whereupon the pivoted relay armature 12 is attracted and closes the circuit of the shunt winding 7,

Patented N ov. 20, 1917-. v

whereupon the resistance of the variable pressure rheostat. 5 increases )to cut down the 'battery charging current.

In the form of regulator shown in Fig. 2,

the charging'of the battery is re lated by i the series winding 6 which contro s the variable pressure rheostat 5 to regulate to some constant value the current supplied to the battery. The shunt winding 7 is normally short-circuted by the short-circuiting device 14, which is illustrated as being a resilient reed carrying 'a Contact, although vother forms may be used, if desired. The

resistance 15 'prevents short-circuiting of the mains 1,2, when said winding 7 is shortcircuited. As the battery approaches a fully charged condition, the counter electro-motive force developed thereby causes an in-l creased energization of the voltage respon# sive winding 16, which thereupon causes the resilient reed 14 to'be drawn down, temporarily opening the short circuit around the winding 7 and permitting the energization thereof. The momentary energization of the winding 7 tends to cause a decrease in the 4pressure applied to the variable pressure rheostat v5 and a corresponding increase in the resistance thereof, whereupon the battery charging current tends to be reduced. l This decrease in current reduces the energization of the coil 16, whereupon the resilient reed 14 is permitted to spring back and again short-circuit the winding 7. The cycle of operation just described is repeated rap-v idly, the vibrations of the reed 14 Ilarying with the increasing tendency of the voltage,

whereupon the mean energization of the winding 7 lis regulated to the extent necessary to control the variable pressure rheostat 5 and thereby oi-set this increasing tendency and gradually reduce or taper off the battery charging current. In order to render the operation' of the device more sensitive, .the auxiliary Winding 17 is preferably provided, which may be connected in circuit in various ways to compensate for the varying reluctance-of the air-gap between the resilient reed and the magnet 16 which causes the vibration thereof. In the connection shown, the auxiliary coil 17 is connected 1n the shunt circuit around the separable contacts and a resistance 18- is included in said shunt circuit. As long as the separable contacts are closed, the coil 17 is short-circuited. Whenever the contacts open, said coil is energized by current which flows from the positive side of the line through the resistance 15 and thence dividing, part of the current flowing through the resistance 18 and coil 17 to the negative side of the line, and the rest of the current iowing through the coil 7 to the negative side of the line. The resistance 18 limits the current iiowing in the coil 17. It will be seen that the coil 17 'is energized whenever the coil 7 is energized and is short-circuited whenever said coil is short-circuited. Both coils are energized whenever the resilient reed is drawn down. The coil 17 is wound differentially with respect to the coil 16 and accordingly opposes the same when energized, whereupon the resilient reed springs back very quickly to again close the short circuit. Accordingly, the vibrations are accelerated and the regulation takes place within very close limits.

It is apparent that either or both forms of regulator described and illustrated may be used in connection with the same mains or in the same charging station, depending on whether the stop charge or taper charge system of battery charging is preferred 1n each case.

It is further apparent that I do not desire to limit myself to the details shown and described, as various changes may be made without departing from the spirit of the invention, as expressed in the appended claims.

What I claim as new and desire to Secure by Letters Patent of the United States 1s' 1. In a battery charging system, astorage .battery to be charged, a source of char g current, a variable resistance connecte in series with said battery, a current responsive winding also connected in series with said battery, mechanical connections between said winding and said resistance whereby said Winding regulates said variable resistance to maintain substantially constant the current supplied to said battery, and means responsive to the counter electro-motive force of said battery for increasing said variable resistance to cut down the battery charging current.

2. A regulator for storage battery charging systems, comprising a variable resistance adapted to -be connected in series with the battery to be charged, a current responsive Winding also connected in series with said battery and adapted to regulate said resistance to maintain the battery charging current at a substantially constant, value, and a voltage coil adapted to respond to the voltage at the battery terminals and vary said resistance to reduce said battery charging current when the battery has become fully charged. 3. A regulator for storage battery charging systems comprising a variable pressure rheostat adapted for ,connection in series' with the battery to be charged, a series coil adapted to control said rheostat to maintain the battery charging current substantially constant during the charging of the battery, and a voltage responsive coil adapted when suiciently energized in response to the increasing counter electro-motive force at the battery terminals, to e'ect an increase in the resistance of said rheostat, thereby reducing the battery charging current when the battery approaches a fully charged condition.

4. A charging current regulator for a storage battery including a variable pressure rheostat, a series winding normally controlling the same, a shunt Winding also adapted to control said rheostat but normally inert, and a voltage responsive coil connected across the battery terminals and adapted when energized to cause the energization ofv said shunt coil for the purpose of increasing the resistance of said rheostat and thereby cutting down the battery charging current.

5. A charging current regulator for a storage regulator` comprising a rheostat composed of a series of contacting resistance plates, a spring normally causing said plates to be pressed together, whereupon the resistance of said rheostat is maintained at a minimum value, a series winding and a shunt winding each adapted when energized, to oppose the action of said spring and increase the resistance of said rheostat, said series winding being connected in the battery charging circuit and normally operating to maintain substantially constant the current supplied to said battery,'said shunt winding being connected across said battery charging circuit and normally inert but adapted when energized to increase the resistance of said rheostat to cut down the battery charging current, and a regulating winding connected across said charging circuit 'between said rheostat and said battery to permit the energization of said shunt winding when the battery reaches a predetermined voltage. v

6. A system of regulation for battery charging including in combination with the battery a variable resistance adapted for connection in series therewith, a series coil adapted to control said resistance to maintain the battery charging current substantially constant as the charge progresses, a shunt coil also adapted to control said resistance, a short circuit around said shunt coil, separable contacts, one of which is adapted to vibrate rapidly to open and close said short circuit, and a voltage responsive winding adapted when suiiiclently energized in response to the increasing counter electromotive force at the battery terminals to cause the vibrationof said contact and to cause a'change in said vibrations as its energization increases, whereby the energization of said shunt coil `is gradually increased and .the battery charging current is tapered of.

7. A system of regulation for battery charging including in combination with the W battery a variable resistance adapted for connection in seriesftherewith, a series coil adapted to control said resistance to maintain the battery charging current substantially constant as the charge pr eases, a shunt coil also adapted to contro said resistance, a short circuit aroundsaid shunt coil, separable contacts, one of which is ada ted to vibrate rapidly to open and close sa'i short circuit, a voltage responsive winding adapted when sufficiently energized inrevoltage.

spense to the increasing counter electro-motive force at the batteryrterminals to cause the vibration of said contact and to cause a change in said vibrations as its energization increases, andan auxiliary coil for accelerating mid vibrations, wherlei the energize.- tion of said shunt coil is g ually increased ard the battery charging current is tapered 0 8. In a battery charging system, a source of supply, a storage battery connected there= to and a regulator having a variable resistance in series with said battery, a c'oil in series with the battery for varying the resistance to hold the battery charging current `lconstant, a second coil connected across the battery terminals adapted when energized to modify the action of the current coil, and a relay having a controlling coil also connected across the battery terminals between the resistance and the battery, said relay controlling the excitation of said second coil and adapted to cause an increase inthe energization of said second coil as the voltage v,

of the battery tends to increase, whereby an increased modifying etect is exerted by said second coil and the battery current is tapered A upon tendency to increase. in the battery In witness whereof, I have hereunto subscribed my name in the presence of two witnesses.

WILLIAM L'.. BLISS.

Witnesses: A. H.` AN,

WM. Fromm 

